This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In this proposal, the investigators will examine the role that the autonomic nervous system plays in heat-induced vasodilation in heart failure. The following hypotheses will be tested: 1) Total skin nerve activity responses to heat stress challenges will be attenuated in CHF patients;2) The attenuated skin vasodilation responses seen in CHF patients are due to increased skin vasoconstrictor activity and/or increased circulating catecholamines;and 3) Baroreflex impairments seen in heart failure will be exaggerated by heat stress.